1. Field of Invention
The invention relates to an electronic device and, more particularly, to an electronic device additionally using ambient light as its light source.
2. Related Art
A liquid crystal display device includes a liquid crystal panel and a backlight module. The backlight module provides the liquid crystal panel with backlight light source, and then the liquid crystal panel can display images.
As shown in FIG. 1, a conventional liquid crystal display device 1 includes a case 11, a light-guide plate (LGP) 12, a light emitting element 13, a plurality of optical films 14 and a liquid crystal panel 15, and the LGP 12 and the light emitting element 13 are used as the backlight module.
Herein, the case 11 consists of an upper cover 111 and a lower cover 112, and the LGP 12, the light emitting element 13, the optical films 14 and the liquid crystal panel 15 are assembled in the case 11. The light emitting element 13 is disposed at one side of the LGP 12, and the light emitting element 13 may be a cold cathode fluorescent lamp (CCFL). The optical films 14 are superposed on the LGP 12, and the optical films 14 may include diffusers, brightness enhancement films, and so on.
In the structural design, the function of the LGP 12 is guiding the scattering direction of the light emitted by the light emitting element 13 to enhance the luminance of the backlight module and ensure the uniformity of the brightness of the backlight module, and the optical films 14 allows the light guided out by the LGP 12 to be further uniform and bright.
However, when a user uses the liquid crystal display device 1 in the sun, the problem that the brightness of the panel is insufficient occurs, which causes besetment in usage. Further, if the brightness of the light emitting element 13 increases to solve the above problem, another problem that it is power-consuming occurs.
Therefore, it is an important subject to provide an electronic device additionally using ambient light as its light source to solve the above problems.